The present invention relates to the use of comprehensive fuel additives for gasoline and diesel fuels intended to improve engine combustion efficiency, improve diesel fuel cetane levels, improve diesel and ultra low sulfur diesel fuel lubricity, reduce engine component friction, reduce engine deposit formation, reduce gasoline and diesel fuel bio-contamination and reduce pollutant exhaust emissions produced by gasoline and diesel fuel powered internal combustion engines. The present invention further relates to the use of fuel additives that do not increase the sulfur level of ultra low sulfur diesel fuel beyond 15 ppm (parts per million).